Need to know more about mbti, need help to understand this better

Ok I got to know about mbti and it's types from a friend. I am sceptical about this but cannot push this aside entirely due to:-

1. I took online mbti test in three different websites (yes i spent some reasonable time of my life taking these tests) and all of them points out me as intj. I even took the test again.

2. I read about intj and I was able to relate to it, but i have only read about intj and Nothing else. So I don't know whether I can relate with other types

3. I think the humans cannot be just categorised into just 16 types, there could be more.

4. Uhh , it may be cringe but I really could relate to many things said here, and it was kinda wholesome. I thought I had mental issues or something and I was seriously thinking about consulting a psychiatrist. But then all the symptoms were listed as my traits??? Like all people who I knew made ton of friends, and I hate that part and thought it was something wrong, there are few more such stuff.

But before confirming whether these are my way of personality or some issue with my eq, I need to know about this in a little depth.

So can you suggest some online documentation on these ? Ok it may not be science based but I really want to know why I am the way I am. I could use ai and I did but did not understand fully, give me some source to learn about this stuff.

Thank you